Protective mesh

The most convenient setup for hydrogenation on an intermediate synthetic scale is the Parr low-pressure shaker-type apparatus (Fig. A3.9), in which variable pressures of from 1 to 5 atmospheres (60 psi) may be safely employed. The compound to be hydrogenated (approx. 100 g) is dissolved or suspended in 200 ml of a suitable solvent in a heavy-walled 500-ml bottle. The bottle is placed in the apparatus and clamped in place inside the protective mesh. The flask is briefly evacuated, then filled with hydrogen to the desired pressure. The reaction is initiated by starting the shaker, and the course of the reaction is easily followed by observing the drop in pressure in the bottle and... 

Principle The EDTA-plasma sample is applied onto the protective mesh. Integrated precipitation and lipoprotein fractionation by means of dextrane sulfate and magnesium ions then take place in the precipitation layer. The precipitated lipoprotein fractions - chylomicrones, VLDL (very low density lipoproteins) and LDL (low density lipoproteins) - are filtered by the transport layer and only the HDL (high-density lipoproteins) fraction reaches the indicator him where the HDL cholesterol concentration is determined enzymatically by the following reaction ... 

The actual medium in a pleated cartridge will have protective mesh (wire or plastic) on its inside and outside, the whole being further protected by a cylindrical perforated plate screen external to the pleats (Figure 3.51). This figure also shows the end-caps sealed to the top and bottom of the pleats to make a coherent filtering element. 

Zirconium is a highly active metal which, like aluminum, seems quite passive because of its stable, cohesive, protective oxide film which is always present in air or water. Massive zirconium does not bum in air, but oxidizes rapidly above 600°C in air. Clean zirconium plate ignites spontaneously in oxygen of ca 2 MPa (300 psi) the autoignition pressure drops as the metal thickness decreases. Zirconium powder ignites quite easily. Powder (<44 fim or—325 mesh) prepared in an inert atmosphere by the hydride—dehydride process ignites spontaneously upon contact with air unless its surface has been conditioned, ie, preoxidized by slow addition of air to the inert atmosphere. Heated zirconium is readily oxidized by carbon dioxide, sulfur dioxide, or water vapor. 

Conveyors may be of parallel-chain, mat, slat, woven wire-mesh belt, or cast-alloy type. Automatic tensioning devices are used to maintain belt tension during heating and cooung. The product may rest directly on the conveyor or on special supports built into it. RoUer-conveyors are used for large pieces. Flame curtains are provided for sealing the ends and for protection of special treating atmospheres. 

Typical applications include primary devv atering of phosphate rock matrix and silica sand products following vv et screening. In ore dressing it is used rnainlv to protect large-diameter thickeners bv scalping out-l-65-mesh material,... 

Geraniol [106-24-1] M 154.3, b 230 , d 0.879, n 1.4766. Purified by ascending chromatography or by thin layer chromatography on plates of kieselguhr G with acetone/water/liquid paraffin (130 70 1) as solvent system. Hexane/ethyl acetate (1 4) is also suitable. Also purified by GLC on a silicone-treated column of Carbowax 20M (10%) on Chromosorb W (60-80 mesh). [Porter Pure Appl Chem 20 499 7969.] Stored in full, tightly sealed containers in the cool, protected from light. 

Factors that are important for the limitation of protected areas are the pipe network structure, degree of mesh, number of service pipes, type of pipe connections, quality of the pipe coating and availability of protection current as well as stray current effects. A protected area in a distribution network is shown in Fig. 10-11 with separate parts of the network (NT I to NT IV). Previous experience has shown that protected areas of 1 to 2 km with lengths of pipeline from 10 to 20 km are advantageous [30],... 

These anodes, like platinised Ti may be supplied in different forms e.g. rod, tube, mesh, wire, etc. They may be used for the cathodic protection of offshore structures, heat exchangers, or even pipelines as they can be installed in the soil surrounded by carbonaceous backfill, and are comparable in cost to platinised titanium. ... 

The anode is fixed to the concrete using non-metallic fixings and may be supplied as a prefabricated mesh or more often as a continuous anode strand which is laid over the surface of the structure to be protected. The spacing between the anode strands may be adjusted to give the required current distribution and current density per unit area of concrete necessary to provide cathodic protection to a particular structure. 

A number of anode connections will be made to the d.c. power source using proprietary splice kits (approximately one for every 60-80 m of concrete to be protected). This will provide redundancy for anode failure and reduce ohmic losses along the anode cable. Care must also be taken not to expose the copper conductor during installation or anode failure could take place. Once fitted to the concrete surface a 15 mm thick cementitious overlay is applied above the anode mesh, as recommended by the anode manufacturer, although thickness of up to 35-40 mm have been applied in some instances. 

The most recently developed anode for the cathodic protection of steel in concrete is mixed metal oxide coated titanium mesh The anode mesh is made from commercially pure titanium sheet approximately 0-5-2mm thick depending upon the manufacturer, expanded to provide a diamond shaped mesh in the range of 35 x 75 to 100 x 200 mm. The mesh size selected is dictated by the required cathode current density and the mesh manufacturer. The anode mesh is supplied in strips which may be joined on site using spot welded connections to a titanium strip or niobium crimps, whilst electrical connections to the d.c. power source are made at selected locations in a suitably encapsulated or crimped connection. The mesh is then fitted to the concrete using non-metallic fixings. 

Hayfield, P. C. S. and Warne, M. A., Titanium Based Mesh Anodes in the Cathodic Protection of Concrete Reinforcing Bars , presented at UK Corrosion, Brighton (1988)... 

In some cases radiation shields are provided to protect against heat effects from fire incidents and operation requirements. The shields usually are of two styles either a dual layer wire mesh screen or a plexy-giass see through barrier. The shields provide a barrier from the effects of radiant heat for specific levels. They are most often used for protection against flare heat and for barriers at fixed firewater monitor devices, most notably at the helidecks of offshore facilities. 

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